REPRODUCTION. 595 



them, we are indebted to the observation and 

 sagacity of Mr. Andrew Knight.* 



The plans hitherto noticed are suited only to 

 the simplest of vegetable or animal beings ; but 

 for the continuance of the higher races in both 

 kingdoms of nature there is required a more 

 complex procedure. The latent germ, contained 

 in the seed or ovum, is never developed beyond 

 a certain point, unless it be vivified by the action 

 of a peculiar fluid, which is the product of other 

 organs. Thus there are established two distinct 

 classes of structures ; the office of the one being 

 the formation of the seed or ovum, and that of 

 the other the production of the vivifying fluid. 

 The effect of this vivifying fluid upon the dor- 

 mant germ is termed FecuHdatioti ; and the 

 germ, when fecundated, receives the name of 

 Embryo. 



The modes in which the fecundation of the 

 germ is accomplished are exceedingly various in 

 different classes of organized beings. In all 

 Phanerogamous plants, (so named in contra- 

 distinction to those which are Cryptogamous), 

 the whole of the double apparatus required for 

 reproduction is contained in the flower. One 

 set of organs contains the rudiment of the seed, 

 enclosed in various envelopes, of which the as- 

 semblage constitutes an ovary, and to which is 



* See his various papers in the Philosophical Transactions. 



